In this article i have explain how to validate textbox using regular expression allow only integer values

Process :-
1 : - Create a new project in asp.net and add new from and drag and drop a text box and provide the id to the textbox.In this article the id of text box is txt_priority .
2 : - Drag and drop the Regular Expression validator on the form and set the property as show below
ID =RegularExpressionValidator1
ControtoValidate= txt_priority [this is textbox id]
ErrorMessage=Please enter numbers only
ForColor=Red
ValidationExpression=\d+